Why first-born children are smarter than their younger siblings, by researchers

*Removing your kid’s appendix is waste of time: Three quarters would be fine with just antibiotics, study finds

First-born children are smarter than their younger siblings, according to new research.

Economists at the University of Edinburgh, United Kingdom (U.K.) have waded into the age-old debate and concluded that first-borns have a higher Intelligent Quotient (I.Q.) test score than their siblings as early as age one. Researchers said the findings could be explained by first-born children receiving more mental stimulation and support in developing thinking skills from their parents during their early years. The findings, published in the Journal of Human Resources, could help explain the so-called birth order effect when older siblings in a family enjoy better wages and more education in later life, according to researchers. The study, conducted in partnership with Analysis Group and the University of Sydney, examined data from the US Children of the National Longitudinal Survey of Youth collected by the US Bureau of Labour Statistics.

Almost 5,000 children were observed from pre-birth to 14 years old on their family background and economic conditions. Every two years they were assessed on skills including reading and picture vocabulary. The tests included reading recognition, such as matching letters, naming names and reading single words aloud. Researchers applied statistical methods to the economic data to analyse how parental behaviour such as smoking and drinking during pregnancy was related to their child’s test score. It was found that mothers took ‘higher risks’ during the pregnancy of latter-born children.

Parents also offered less mental stimulation to younger siblings and took part in fewer activities such as reading, crafts and playing musical instruments. The findings showed that advantages enjoyed by first born siblings start from just after birth to three years of age. Parents changed their behaviour as subsequent children were born.

Also, a landmark British study suggests that operating on children with acute appendicitis may be unnecessary in the majority of cases. Removing an appendix is the most common form of emergency surgery performed on children in the UK. One in 12 people develop appendicitis at some point in their life, and it is most likely to strike between the ages of ten and 20. The problem occurs when the appendix, part of the digestive tract, becomes infected and inflamed.

Removal has been the standard treatment for appendicitis for more than a century.
But experts at Southampton Children’s Hospital have now found simply treating the problem with antibiotics can be just as effective.

They found that among children with a common forms of acute appendicitis, called an ‘appendix mass’, three quarters could be safely treated without surgery.

Avoiding an operation would mean children could avoid the pain of surgery, would not have to undergo general anaesthetic, and might not even need an overnight stay in hospital.

And although it is a relatively straightforward operation – and has become safer over the decades – any invasive procedure carries risks. The researchers found severe complications occurred in six per cent of cases. Currently most doctors treat an appendix mass with antibiotics, but then remove the organ to ensure the infection does not return – a procedure known as an ‘interval appendicectomy’.

But the researchers, writing in the Lancet Gastroenterology and Hepatology journal, said this ‘surgical dogma’ should now be changed in light of their findings.

Dr. Ana Nuevo-Chiquero, of the University of Edinburgh’s School of Economics, said: “Our results suggest that broad shifts in parental behaviour are a plausible explanation for the observed birth order differences in education and labour market outcomes.”

Since families are shrinking, with fewer parents having more than two children, a greater proportion of people today are firstborns than in the past. So if firstborns are more likely to be overweight, that will push up obesity rates.

The scientists also said there is mounting evidence that firstborns are more at risk of health problems such as diabetes and high blood pressure in later life than their siblings. But the underlying causes for these differences are far from clear, they added.

Writing in the Journal of Epidemiology and Community Health, the team said: “Our study corroborates other large studies on men, as we showed firstborn women have greater BMI and are more likely to be overweight or obese than their second-born sisters.”

Study leader Nigel Hall, a consultant paediatric surgeon at Southampton Children’s Hospital, said: “Up until now more than two-thirds of surgeons were routinely recommending interval appendicectomy. Yet the justification for this surgical intervention has never been prospectively challenged.”

He said experts had previously assumed roughly a fifth of cases of appendicitis would return if the appendix was not removed. “But we have shown that figure is much lower,” he said.